GAP Australasian-Dentist Issue 80 Jul-Aug 19

Category AustrÀlÀsiÀn Dentist 61 n aÀ defects of epithelial tissues: 49 À u Congenital erythropoietic porphyria À u Àctodermal dysplasia À u Àpidermolysis bullosa À u Àuberous sclerosis 2.À Hereditary conditions associated with defects in mineralisation pathways: À u DiGeorge syndrome 50 À u ÀVitamin D dependent rickets, 51 Vitamin D resistant rickets, 52 pseudovitamin D deficiency rickets 53 3. À Dentinogenesis imperfecta 54 4. À Amelogenesis imperfecta: 55 À u Hypoplastic À u ÀHypomineralised: hypomaturation (including hypomaturtion- hypoplastic with tuarodontism) andÀhypocalcified 5. À Cystic fibrosis 56 Bleaching has been shown to be successful in the minimal invasive treatment of hereditary conditions especially amelogenesis imperfecta 57 and dentinogenesis imperfecta. 54 Àhis is extremely beneficial for such patients as preservation of existing enamel is crucial in such conditions. Àensitivity may also be an issue for patients with hereditary defects and adequate sensitivity prevention is required. Traumatised/non-vital teeth Discolouration associated with trauma or loss of tooth vitality can be very severe and range in colour from yellow, black, brown, purple and grey (as seen in Figure 8). Haemorrhage of the pulp is the most common cause of discolouration after trauma. Blood enters the dentinal tubules and then decomposes leading to a deposit of chromogenic blood degradation products, such as haemosiderin, hemine, haematin, and haematoidin. Chromogenic degradation products also result from pulp necrosis. 58 Calcific metamorphosis may also results in discolouration and is commonly seen as early as three months after traumatic tooth injury. Àt is characterised by the deposition of hard tissue within the root canal space and a yellow discolouration of the clinical crown. 59 Discolouration may result from iatrogenic induced causes following treatment of the non-vital tooth. Àhese include: u Àoot canal cement or gutta percha in the coronal portion of the access cavity u Àemnants of the pulp and pulp horns following access cavity preparation 60 u Combining sodium hypochlorite (even at low concentrations) and chlorhexidine irrigation which may result in formation of brownish-red precipitates. 61 Àt is essential that iatrogenic causes are appropriately identified and managed before commencing with bleaching treatment. Discoloured teeth with a history of trauma should undergo vitality testing and if no previous radiographs have been taken, appropriate radiographic assessment should be undertaken to ensure appropriate treatment is undertaken prior to and post bleaching. 62 A single discoloured tooth which retains vitality, for example in calcific metamorphisis, 59 should not have elective root canal treatment undertaken. Àhese patients should rather be provided with a ‘single tooth’ bleaching tray as seen in Figure 9 and bleaching agent applied externally, solely to the targeted discoloured tooth. Àhis is because externally applied bleaching material diffuses readily through teeth and uniformly changes dentine shade throughout, regardless of depth. 63 Àhere are several different non-vital bleaching techniques and these have been described elsewhere in the literature. 64, 65 Àhe author would recommend the inside/ outside closed bleaching technique for the adolescent patient. Àhis involves sealing 10% CP into the pulp chamber and providing the patient with a ‘single tooth’ bleaching tray, who continues bleaching externally at home. Àhis technique allows for adequate cleaning of the pulp chamber without the associated risks of leaving the access cavity open and allows repeated frequent application of bleaching agent externally, thus allowing maximum whitening of the tooth without the patient returning to the practice. Àome may choose to utilise the inside outside open technique. Àhis would involve leaving the access cavity open to allow frequent replacement of the bleaching agent intracoronally, which would otherwise become inactive up to ten hours post application. As mentioned previously, this is unnecessary due to the rapid penetration of bleaching material through the tooth from the external surface. Furthermore, this may also potentially jeopardise the root canal treatment, if the patient fails to keep the access cavity appropriately clean or fails to return in a timely fashion for the access cavity to be closed. As such, this technique should only be used on well-motivated patients who are excellent attenders and with excellent oral hygiene. Systemic diseases Àumerous systemic diseases can lead to discolouration including but not limited to: u Premature birth and low birthweight 66 u Diseases of the blood 67 u Àeonatal jaundice u Àeonatal kidney and liver disease. 68 Antibiotics used to treat systemic infections, such as tetracycline, 69 amoxicillin 38 and ciprofloxacin can also lead to discolouration of teeth. Àhe discolouration experienced as a result of systemic disease is most likely to be intrinsic in nature and, as such, requires prolonged bleaching. Àetracycline staining has been shown to require up to six months of prolonged custom tray-applied 10% CP bleaching to ensure a satisfactory effect. 69 Àhis whitening effect has been shown to remain in 60 and 90-month follow up studies. 70, 71 Fig. 9 A ‘single tooth’ bleaching tray is a vacuum formed custom bleaching tray whereby windows have been cut from the labial of the tray on the teeth adjacent to the target tooth